Variable traffic signal



May 16, 1939. R. o. NELSON VARIABLE TRAFFIC SIGNAL Original Filed May16, 1925 2 Sheets-Sheet l /7 /8 I. L Z

172%??2507 ROBERT 0 1V5; so/v u flarmgy R. O. NELSON v VARIABLE TRAFFICSIGNAL May 16, 1939.

Original Filed May 16, 1925 -2 Sheets-Shee't 2 Jrwewfiar ROBERT QA/zzsaujzforngy ReissuedMay 16, 1939 UNITED STATES PATENT OFFICE VARIABLETRAFFIC SIGNAL Robert 0. Nelson, deceased, late of .Portland,

0reg., by the Engineering & Research Corporation, East Norwalk, Connassignee 25 Claims. (Cl. 177-337) This invention relates to tratliccontrolling and regulating devices, and the primary object is to providean automatic signalling device at the intersection of a main or arterialhighway and a cross road which ordinarily accommodates a lesser amountof traflic, whereby the .right of .way will be constantly maintained onthe highway until a vehicle on-the cross road approaches theintersection, whereupon the signalling system will be reversed, by beingactuated by such vehicle, to give it the right-of-way across thehighway, after which the right-of-way signals again revert to thehighway of main trafilc. A further object consists in providing meanswhereby the right-of-way will be automatically alternated for periodsof, for instance, thirty seconds to each road when traiilc is constantlyapproaching the intersection on the cross road. 'Still further and morespecific objects will be disclosed in the course of the followingspecification, reference being had to the accompanying drawings,wherein:

Figure l is a plan view of a street or road intersection, showing theposition of the trigger switches in the cross road.

Figure 2 is a sectional elevation through one of the trigger switches.

Figure 3 is a diagrammatic plan view, showing the wiring and connectionof the electrical con trol system.

Figure 4 is a plan view of amagnetic switch employed in the circuitsystem.

Figures 5 and 6 are end and side views, respectively, of the switchshown in Figure 4.

Figure 7 is a sectional elevation on the line 7-1 in Figure 4.

Figure 9 is an elevation of an alternator used in the device.

Figures 8, 10, ll, 12, and 13 are sectional views as seen substantiallyon the respective lines 8-8, Ill-l0, li-ll, l2l2,' and l3-l3, in Figure9.

Referring to the drawings more particularly and by reference characters,A designates a north and south street, lane'or road, hereinafterreferred to as the highway, whichis crossed by an east and west streetB, hereinafter designated as the cross lane, or road, and adjacent thejuncture or interfering point of these traflic lanes, as at the middlepoint of the intersection is a conventional signalling standard C, inthe base of which may be arranged the control box D of the traiilcsignaling apparatus. The signals may be of any 01' the well known typesfor indicating right of way for one or the other lane. In the embodimentillustrated Stop" and "Go signs are electrically lighted and alternated"so that when the sign reads Stop" in one direction it will read Go" inthe other or cross direction, and vice versa. Thus in Figure 3 I haveindicated signal lamps R, R as the red or stop lamps for I the highway,and these lamps are circuitously connected with the lamps G, G, whichare the green or Go lamps of the cross read; while the R R Stop lightsfor the cross road are connected in circuit with and are simultaneouslyenergized with green (30" lamps G G which give the right-of-way to thehighway traflic, and stop the cross road lane trafllc. It will bepercelved that the apparatus illustrated utilizes visual signals Thecircuit controlling mechanism (later to be described) which controls thetwo circuits to the lamps in the signal is preferably contained withinthe control box D, and the trafllc situation on the cross road isindicated and communicated to this mechanism through auxiliary circuitswhich are controlled by what may be conveniently termed controllers, ortrigger switches E and -F These controllers are actuated, in theembodiment illustrated being closed by the passing of vehicles over themeach vehicle serving to cause a single actuation of the controller E orF as the case may be. These switches are secured in the street or road Band are arranged on the approach side of the signal and in the path oftravel of the vehicles about as shown in Figure 1.

As illustrated, the controller E or F occurs in but one lane, the crosslane.

The design or construction of these controllers or trigger switches maybe greatly varied and modified, but a preferred form is illustrated inFigure 2 and is substantially the same as the trigger switch shownin-Figure 3 of co-pending application for patent Serial No. 695,596,which was filed on February 27, 1924, for Automatic variable traflicregulator. It consists, primarily,

of a box or casing I3 which is imbedded in the street, and has a plateI0 pivotally secured therein, as at H. The swinging end of the plate I!)has a flange H which tends to keep the box closedwhen the-plate is inits raised position and as not being depressed by a vehicle. The plate II) is normally retained in an inclined or raised position as shown, by aspring I, but when travelled over by the wheel of a vehicle is depressedto a flush or horizontal position, where it stops. A pair of switchterminals I5 and is are, respectively, secured to the plate l0 and boxI3, and close together when the plate is depressed, and thus close a'circuit through wires" l1 and I8 which lead to the control box througha suitable conduit.

Before tracing the circuits in and to the control box andto the lightinggroup and trigger switches, the mechanism or mechanical strut:- turecontained within the control box will first be described as follows: r

The magnetic switch device shown in Figures 3, 4, 5, 6,.and '1 consistsof a suitable base having an end wall 3| and an intermediate wall 32. Asolenoid 23 is mounted on the base and serves, when energized, to pull alever 24 down against the yielding tension of a spring 23. When thesolenoid is deenergized, the spring 25 tends to restore the lever 24 toits upper position, as shown in Figures 5 and 6. This upward movement isretarded, however, by,, an air check consisting of a pivoted cylinder2|? in which operates of a wire 39 is mounted at a piston 21 which isconnected to the outer extremity of the lever 24. A second lever member29 is arranged parallel with the lever 24, and,

like the latter, is pivoted at its rear end to the wall 3|, while theforward ends of both levers are guided by being slidable in verticalslots in the wall 32. The lever 29 is yieldingly raised by a spring 33,and is depressedby a laterally proiecting finger 25 of the lever 24.When the lever 29 is released by the finger 25 it is retained in itslowered position by a bell crank catch member 31, which is pivoted on 32and retained by a spring 38. When the lever 24 now returns to its fullupward positions, it moves the member 31 to release the lever 29,whereupon the latter may also return to its upward position. Theterminal the outer end of the lever 29 so that it will close a switchwith a wire 43 the terminal of which is stationary on the wall 32. Thisterminal and switch thus form a make and break device for the circuit ofwires 39-43. 39 is also a supply wire to the solenoid 23. The lever 24is arranged to be retained in its lowered position by a bell-crank hookmember 34, which is retained in engagement with the lever 24 by a magnet35, supplied by wires 43 and 5 9,. but which is'released by a spring 35,when the magnet is de-energized. The alternator indicated in Figure 3and shown more in detail in Figures 8 to 13, inclusive, will now bedescribed as follows: A shaft 49 is journaled in suitable end brackets49". A drum 59 is rigidly secured on the shaft to rotate with it, and adrum 5| is rotatably mounted on the shaft. The drum 59 has a ratchetwheel 49 adapted to be engaged by a timing unit or mechanism T when acircuit is closed through the wires 43 and 54,

The timer T may be of any common and well known construction which iscapable of lifting and dropping an arm or dog at regular intervals so asto turn the ratchet wheel 49 the length of one tooth for eachelevation-of the dog. A

pawl 91 is brought to bear against the ratchet wheel 49 by a magnet 63which is also placed in the circuit 43-54. It will thus be seen that thepawl 51 will prevent the reverse rotation of the ratchet wheel when thelatter is being rotated by the dog 53, but will allow the wheel toreturn to its initial position when the timer is inactive and thecircuit 43-54 is broken. Thus it will be seen that if the circuit 43-54is energized continuously the timer will at periodic and regularintervals lift the arm 39, causing ratchet wheel 49 to be rotated toothby toothat a den nite rate which is determined by the space be- .tweenthe teeth on the ratchet wheel and by the wheel 49 in two minutes. Whenthe circuit 43-54 is de-energized, the timer T becomes inactive, and thepawl 61 is released by magnet 66, thereby permitting drum 59 withratchet wheel 49 and the accompanying commutator to be returned byspring 69 to its normal position so that either tripping lug 13 or 14 isat rest against projection 15.

Within the drum 5| the shaft is enlarged as at 49 (Fig. 11) and to it isfastened one end of a coil spring 59, the other or outer end of which issecured to the inner face of the drum. Now when the shaft is rotated, bythe drum 59, the spring 59 winds itself about the shaft. The drum 5| isheld stationary, against the rotating tendency of the spring, .by a pawl'12, which is held against the periphery of the drum by a spring 13, andreleasably engages the stop or lug 19 or 1| on the drum. As the shaft 49continues to rotate it will be evident that the spring tension wouldsoon become excessive, and to relieve this tension (without reversingthe drum) the drum 59 is provided with a pair of diametrically opposedtripping lugs 14 and 14', which at certain intervals in the movement ofthe drum 59 act against a projection 19 of the pawl 12, and releasethelatter from the lugs 19, 1|. To prevent the drum 5|- from returning toorapidly, when so released, a small governor 1B is provided which isoperatively associated with the drum through gears 11 and 52.-

When the ratchet wheel 49 is freed from the timer T, the spring 59 willreverse the direction of the shaft and also the drum 59. This reversemovement is checked, however, by the arm 15 of the pawl 12, whichengages either of the teeth 14 or 14 to stop the drum 59 in an initialposition.-

I On the drum 59 .is a peripheral path 49-43 (Figs. 9, 19)havingalternating conducting and non-conducting areas, the conductingareas providing contacts which rotate in contact with contact brushes 44and 45, which are yieldingly retained in contact with the path bysprings 41, and

which are terminals for wires "and 4|, respecdrum contacts and the brushcontacts 44 and 45 provide a switch, wherewith circuit may be made andbroken with wires 4| and 42. As the highway right of way controllingcircuit includes wire 42, and the cross lane right of way controllingcircuit includes wire 4|; shift of the switch contacts just' mentionedis cooperative to shift right of way indication as between the highwayand the cross ane.

The circuit wiring will now be set forth. Wires 2i andihrepresent thepower supply, which, for convenience in tracing, we can assume to bepositive in wire 2|, and negative in wire 22. When there is no crossroad trafllc to actuate the switches E or F there will be a closedcircuit through the elements 2|, 54, 49 49, 43, 43", 43, 45, 42, 51, and22, thus lighting the lamps R R and G G and givinga constant rightofway' to the tramc on the highway. Now when aneast or west boundvehicle approaches the intersection on the cross road where the signalis located, it depresses the plate ll of the trigger switches E or F,and in so doing closes a circuit between the wires :1 and I8, andenergizes the solenoid 1 23, via 39 and I8, resulting in the closing ofa contact between the terminals 39 and 43 as above described. The wire43 now gives a negative supply to the magnet 35 and the timer T of thealternator, and the wire 54 carries a positive charge to the timer T andto the contact areas 48. Thus the timer T is actuated as soon as thecontact between 43 and 39 is made. A branch 59 of the wire 42 carries apositive charge, when the terminal 42 has contact with 48 of thealternator, to the retention magnet 35, and consequently the magnet 35is energized while the make and break device 43-39 is closed. When acircuit is closed through wires 42, then the signal lamps G G and R Rare supplied, signalling the right 01" way to the highway traflic as 51is the negative wire to all the lamps, and when the wire 4| is chargedthen the opposite'lamps G, G, R, and R are energized, to signal theright of way to traihc on the cross road.

In order that a bell signal of short duration may be given, as the rightof way is changed from one direction to the other, a thermal switch 85is provided in each of the circuits of 4| and'42. Each of these switchesis constructed so that it will break the circuits through wires 83 and64, to the bell 6|, shortly after the current starts flowing in 4| or42. To avoid "short circuits" separate circuits are provided for thebell by way of a negative wire 62 to the wire 51.

Having now described the construction and action of the device and itsvarious parts; assume that a single vehicle approaches on the crossstreet and indicates its presence by actuating the controller, ortrigger switch E, for example. This action energizes solenoid 23 andcauses arm 24 to repress its associated arm 29 and close a circuitthrough contacts 39, 43. When these contacts are closed the timer T isenergized, and also operates as a motor part and rotates'thealternator-58 so that insulation section 48 engages a fixed contact 45and interrupts highway light circuit 42 so that the green lights on thehighway and the red lights on the cross street indicative of right ofway on the highway are extinguished. Simultaneously with this movementright of way is transferred to the cross lane because a contact section48 engages cross lane, brush contact 44 and energizes the cross lanelight circuit 4|, thus,

causing a Stop signal to be given to the highway and a "(30 signal tothe cross street, and the vehicle is given a definite time to cross theintersection.

The period of time given the vehicle to cross the intersection iscontrolled by the air check 28 which is brought into operation at theinstant highway circuit 42 is interrupted. When circuitset back tonormal position by the action of spring 99. The return movement of thealternator interrupts circuit 4| and restores circuit 42 to normalcondition so that the "Go" signal is returned to the highway and the"Stop signal to the cross street.

In the event that there is a continuous stream of traific on the crossstreet, the arm 24 is repeatedly drawn down by solenoid 23 and the timerTis constantly energized so as to rotate the alternatcr at a uniformrate so that the'right of way is alternately given to each street fordesired predetermined periods of time. The time is regulated by thearrangement of the segments 48 and 48 on the alternator or switch. Whenthe apparatus is in idle condition awaiting actuation by trafiic, thehighway contact brush 45 lies against contact segment 48, thuscompleting circuit to the lights indicative of highway right of way.Obviously therefore the period of duration of highway right of way isdependent on the time period of this mutual contact of brush 45 andsegment 48. For exemplary purposes of this disclosure, this contactlasts 30 seconds, at the uniform rate of the motor part T. Should therate of this motor part be varied the time period of contact may beincreased or decreased as is apparent.

One important feature of the invention is that when traflic on the crossstreet has maintained the right of way for a maximum period of thirty.seconds, for example, the right of way is automatically taken from thecross street and given to the highway for an equal period of thirtyseconds, even though other approaching vehicles have indicated theirpresence on the cross street.

This right-of-way period for the highway tramc cannot be interruptedbecause the continuous arrival of vehicles on the cross street hasre-energized solenoid 23 repeatedly, drawing down arm V 24 repeatedlyinto its down position, thus maintaining contacts 39 and 43 closedcontinuously. Meanwhile the timer T has rotated the alternator 58 untila non-conducting area 48 has been brought into contact with stationarycontact 44 while a conducting area 48 has been brought into contact withstationary contact 45. This has deenergized the circuit through 4| whichgives the Go" signal'to the cross street and the Stop signal to the mainhighway, and has energized the circuit through 42 which gives the G0signal to the main highway and the Stop" signal to the cross street.Simultaneously with the energizing of this circuit, magnet 35 has beenenergized, and arm 24 is locked in its down position I by catch 34. Thetimer continues to rotate the alternator for another thirty seconds, forexample, at the end of which time the movement of the segments hascaused circuit 42 to be interrupted and circuit 4| closed so that theright of way is again given to the vehicles waiting on the cross streetso that they may proceed across the intersection. When circuit 42 isinterrupted. magnet 35 is de-energized and latch 34 releases bar 24 sothat it mayslowly rise, and if no other vehicle approaches on the crossstreet to operate the trigger switch E, the arm 24 reaches its upwardlimit in about ten seconds and thereby opens contacts 39-43 and thusde-energizes the timer and permits the alternator to reset to normalposition as previously described.

It will be perceived from the foregoing that notwithstanding the trafllcactuated controller E or F may be found in but one lane, nevertheless,in conjunction with other elements of the apparatus, the traflic in bothlanes is automatically controlled in a practical and eificient way. Whenthe apparatus is idly awaiting traflic and but one vehicle approaches,the single actuation of the controller by said vehicle causes right ofway indication to be transferred from the highway to the lane of thecontroller and retransferred thereafter to the highway, all withoutfurther actuation of the controller. But it will be noted that thistransfer and retransfer is depending upon actuation of the controller bythe vehicle and is accomplished by actuation by but one vehicle. It willfurthermore be noted that in accordance with the construction described,there is always at least a predetermined period of several seconds, inthe present embodiment 15 seconds, after said actuation of thecontroller,

during which the right of way remains with the highway before beingtransferred to the cross lane. This not only affords opportunity for anyclose highway traffic to pass the intersection before the transfer ofright of way to the cross road but it also affords at least apredetermined period of highway right of way after said retransfer tothe highway and before further transfer to the cross lane as willhereinafter appear.

It will be noted that the single actuation of the controller E or Fresults in lowering the lever 2| by energization of the solenoid 23, andthat repeated actuation of the controller repeatedly lowers said leverin the event that the latter has risen. When the lever 24 is loweredduring highway right of way, it is locked down by the magnet 35, themotor circuit 43 being simultaneously energized through the make andbreak device 39-43. As soon as the drum switch has rotated sufficientlyto cut out the highway circuit wire 42, the cross lane wire ll will beenergized through its brush making contact with a rotating contactsegment 48 and, as the magnet 45 is deenergized at this time because thewire 59 is deen ergized, the lever 24 may immediately begin to rise andeventually in at least a predetermined minimum period of time to causebreak of the motor circuit, whereupon the drum will imme-. diately berotated to cut out cross lane brush contact 44, and thus, at the end ofthis predetermined minimum period, cut out the cross lane right of way.If no other vehicle actuates the controller within this minimumpredetermined period, the motor circuit will be broken at the make andbreak point 3943, cross lane right of way will cease to endure, and theapparatus will operate automatically to retransfer right of way to thehighway as will be apparent'from the explanation already given. However,should a second vehicle actuate the controller before the ex piration ofsaid predetermined minimum period, that is, before the lever 24 hasrisen sufficiently to actuate the bell crank 31 to release lever 29,said lever 24 will be lowered and the motor circuit will remain closedat the make and break device 39-43, so that the motor will continue tooperate and rotatethe drum 50.

Thus successive actuation of the controller during cross lane right ofway, each succeeding actuation being within the predetermined minimumperiodfrom its prior actuation, will cause the cross lane right of wayto endure and be prolonged to beyond said predetermined minimum period.

@ Eventually the cross lane brush-contact 44 will -vlce', or timer; 2.minimum period timer, as it were. When only one vehicle has actuated thecontroller, this minimum period timer will time during cross lane rightof way and will terminate cross lane right of way at the end of theminimum predetermined period of, for example, seconds, successiveactuation of the controller as before explained being required to causeduration in the lane of the controller uninterrutedly to continue forgreater than said minimum period.

It will also be perceived that the drum switch operated by its motortimer T serves as a timing device or mechanism for each right of way,inasmuch as in this particular embodiment, each right of way isdependent upon contact of the controlling circuits 4| or I! at thisswitch. These two timing devices form a timing mechanism cooperable byaction of the apparatus to vary the duration or period of continuity, ofright of way indication between a predetermined minimum and a greaterperiod of time in the cross lane, and one of these devices is cooperableto prolong right of way indication in the lane of the controller to fromat least a predetermined minimum period up to a predetermined maximumperiod, the period being variable in accordance with the intervalbetween successive actuations of the controller. In the cross lane,duration of right of way indication, for at least a predeterminedperiod, is compelled before transfer to the highway and, after transferto the highway, duration in the highway for at least a predeterminedperiod is compelled before further transfer to the cross lane.

When the controller is actuated at such intervals that successiveactuations are not within the predetermined minimum timing intervalafforded by operation of the dash pot timer, but are outside suchinterval, the resultant right of way in the cross-lane from each suchcontroller actuation will continue only for the predetermined 'minimumperiod, as will readily be seen.

It will be apparent that, in the present embodiment, duration of crosslane right of way beyond the predetermined minimum period is dependenton closure of the motor circuit beyond such minimum period. As the motoroperates during cross lane right of way, the mutual contact of the drumswitch contacts for the cross lane circuit endures for a time dependentalso upon the actuation of the controller EF. If the controller isactuated successively within the aforesaid predetermined minimum period,this mutual contact may endure for the full length of the cross lanecontact segment of the switch, whereas if the motor circuit is cut outat the end of the minimum predetermined period the time period of thismutual contact would be less because, as soon as the motor circuit wasbroken by the minimum period timer, the mutual contact at the switchwould be immediately broken on account of the transfer to the highway,right 'the two lanes, the other timer cooperating to vary but one ofthese rights of way namely the cross lane right of way, time control ofthe highway right of way being practically independent of operation ofthe controller actuated timer. In the present embodiment the drum switchtimer provides a maximum control period for each lane, whereas the othertiming device has at least a predetermined minimum control period whichis effective to limit the right of way as determined by the drum switchtimer for the cross lane.

It will be perceived that the invention provides devices operative tocause at least a predetermined minimum timing period which isenlargeable by action of the controller. The dashpot lever 24 may bedrawn down by controller energization of the solenoid 23, before thelever reaches its upper limit. If it is drawn down shortly after itbegins to rise a certain amount of prolongation results. If the leverrises further before being drawn down an increased amount ofprolongation results. Thus prolongation of right of way beyond theminimum interval of time will be increased as the lapsed time betweenthe beginning of one interval and the beginning of the next succeedinginterval increases.

During cross lane right of way, should the controller not be actuatedbefore the lever it rises sufliciently to cause breaking the contact 39,43; that is, not before close of the minimum timing period, duration ofright of way in the cross lane will be concluded at the end of theminimum timing period. Thus duration of right of way in the lane of thecontroller beyond the minimum period is dependent upon the actuation ofthe controller after the inception of and before the close of theminimum timing period. Also it will be perceived that successiveactuation of the controller is adapted to give a greater period ofduration of right of way in one of the lanes,

the cross lane, than is a single actuation of the determined minimuminterval to a maximum in-, I terval by actuation of the controller, thismaxi mum interval beingcapable of adjustable variation as determined bythe rate of movement of the motor mechanism. V

Inasmuch as an important feature of the in vention concerns theindication of right of way for the highway when the traihc approachesthe intersection, the construction provides for compelling highway rightof way subsequently to be indicated, once the right of way has beentransferred to the cross lane. In the present embodiment, upon a singleactuation of the controller, the highway circuit 42 is remade byautomatic operation of the apparatus after it is once broken and withoutfurther actuation of the controller. Once the motor mechanism is startedin response to actuation of the controller, at least a predeterminedinterval of time eiapses before the motor mechanism is arrested. It willbe seen that the minimum period timer assures this.

It is further understood that various modifications may be made in thedesign and structural details herein exemplified, without departing fromthe invention. M

The word time used hi this specification and appended claims withrespect to signal periods or timing mechanism means measured time suchas that measured by a clock or other chronometer, as distinguished fromindefinite or haphazard time of arrival and passage of vehicles.

Having now, therefore, fully shown and described the invention, what isclaimed to be new and desired to be protected by Letters Patent is:

1. A signalling system arranged at the intersection of a highway and across road for regulating trafllc, said system including a highway lampcircuit and a cross road lamp circuit, a time controlled switchassociated with said circuits, ior alternately opening and closing thesame, said switch being normally idle in an initial position so as tonormally retain the highway circuit closed and permit highway traflic tocross the intersection, means actuated by a vehicle approaching theintersection on the cross road for actuating the switch so as toalternately deenergize the highway circuit and energize the cross roadcircuit to successively signal the rightof-way to the cross road andhighway, said means including the. time controlled switch and beingoperative for automatically restoring the switch and the lamp circuitstotheir initial conditions.

2. A street crossing signalsystem including a pair of signal circuits,one circuit including a signal to indicate Stop and the other toindicate Go, switching means normally maintaining the (30 signal circuitclosed and the Stop signal circuit open and movable through a cycle tofirst reverse and then restore to normal the circuit conditions,normally inactive time controlled means for moving said switching meansthrough its cycle, vehicle actuated means for rendering said timecontrolled means active, and means operated by the switch at the end ofits cycle to render the time controlled means again inactive.

3. A street crossing signalling system including a pair of signalcircuits, one circuit including a signal to indicate Stop and the otherto indicate Go, switching means movable through a cycle for alternatelyenergizing said'circuits, normally inactive time controlled means formoving said switching means through its cycle. vehicle actuated meansfor rendering said time controlled means active, and means including theswitch for restoring the time controlled means to its inactivecondition.

4. A street crossing signalling system including a pair of signalcircuits, one circuit including a signal to indicate Stop and the otherto indicate G0, switching means movable through a cycle foralternatelyenergizing said circuits, normally inactive time controlledmeans for moving said switching means through its cycle, vehicleactuated means for rendering .said time controlled means active, andmeans operated by the switch at the end of its timed cycle for renderingthe time controlled means again inactive.

5. A streetcrossingsignalling system'including -a pair of signalcircuits, one circuit including a signal to indicate Stop and the otherto indicate Go, the Go signal circuit of which is normally closed andthe Stop signal circuit open, a nor mally inactive time controlledswitching means for successively and alternately reversing the open andclosed positions of the circuits for predetermined periods of time,vehicle actuated means for rendering the switching means active. and meaincluding the time controlled switching means for rendering theswitching means inactive so as to restore the circuits to their initialconditions.

6. A street crossing signalling system including (A) a pair of signalcircuits, one' for. the cross street and one for the highway (B),switching means having a normally inactive position and movable througha cycle for alternatelyenergizing said circuits (0), normally inactivetime controlled means for moving said switching means' through itscycle, said time controlled means.

comprising (a) motor means adapted to move the cyclic switching meansfrom normal position through cross street and highway positions and tothe normal position, (b) a controlling switch for said motor means, (c)a timed latching device adapted to hold the motor controlling switchclosed in the cross-road position, and (d) a timed latching deviceadapted to hold the motor controlling switch closed in the highwayposition (D), vehicle actuated means for rendering said time controlledmeans active, comprising a traiiic actuated device adapted momentarilyto move the motor controlling switch to its latched position, and (E)means including the cyclic switch for restoring the time controlledmeans to its inactive condition comprising (1) means controlled by thecyclic switch for maintaining the cross-road latch closed for apredetermined time in the cross-road and releasing it after the highwaylatching device has become eifective for the highway time period, and(2) means for releasing the highway latch after a predetermined timeperiod ending in the cross-road position, said highway latch remainingreleased unless the cross-road latch has been latched by-a vehicleactuation during the highway or normal positions.

7. A street crossing signallingsystem including a highway right-of-waycircuit and a crossroad right-oi way circuit, a cyclic switch for said.

circuits having a normal rest position from which it is adapted to bemoved through a cycle to, alternately energize said circuits and returnto normal, timing motor mechanism actuatable for moving said cyclicswitch through such cycle at a predeterminedtime rate to providepredetermined time periods of right-of-way tor the highway and thecross-road, trailicactuated means in the cross-road, a holding deviceoperable initially by actuation of .said traflic actuated meansandeflective for actuating said motor mechanism in said rest position toinitiate such cycle and for maintaining said motor mechanism actuated insuch cycle after such initiation, a time control ,connection betweensaid holding device and said cyclic switch to render said holding deviceineffective in the cross-road part 01 the cycle in order to prepare saidmechanism to terminate cyclic operation in said rest position, a timecontrolled actuating device for said motor mechanlsm connected with saidcyclic switch to be operated'by the latter in the cross-road part of thecycle to actuate said mechanism after release of said holding device toprovide a time period of cross-road right-oii-way and thereafter toreturn said cyclic switch to normal to complete such cycle, the saidcontrol connection being operated by said cyclic switch to render saidholding device again efiective throughout the highway part of the cycleto be re-operated by any further actuation oi said trailic actuatedmeans in the highway part of the cycle to continue cyclic operation foranother such cycle before termination in the normal rest position.

8. A street crossing signalling system including a highway right-of-waycircuit and a cross-road right-of-way circuit, a cyclic switch for saidcircuits having a normal rest position from which it is-adapted to bemoved through a cycle to alternately energize said circuits and returnto normal, trafllc actuated means in the cross-road,

operating said time controlled mechanism for switch through its cycle toprovide a minimum predetermined time period oi highway right-ofway and aperiod of cross-road right-of-way variable between definite minimum. andmaximum time limits and connected with said tramc actuated means so asto initiate such" cycle in reand each connected with mined time periodto provide said maximum time limit, driving mechanism for said cyclicswitch forming a part of said operating mechanism and connected to beactuated by the first timing device at the end or its timing period toreturn said switch to normal to terminate energization of saidcross-road right-of-way circuit, said first timing device being adaptedto be reset to repeat its time period and having linkage with saidtraflic actuated means rendered efiective by said cyclic switch in saidcross-road period of such switch to so reset said timing device bytrafllc actuation whereby said cross-road period will be prolonged bysuch traflic actuation within said maximum time limit.

9. A street crossing signalling system including a highway right-of-waycircuit and a crossroad right-of-way circuit, a cyclic switch for saidcircuits having a normal rest position from which it is adapted to bemoved through a cycle to alternately energize said circuits and returnto normal, traiflc actuated means in the. crossroad, time controlledmechanism for operating said switch through its cycle to provide aminimum predetermined time period of highway right-of-way and a periodof cross-road rightof-way variable between definite minimum and maximumtime limits and connected with said traflic actuated means so as toinitiate such cycle in response to traifio actuation in the restposition, two timing devices forming a part of said mechanism to controlsaid variable time period said cyclic switch to be initiated intooperation bythe latter in the cross-road part of its cycle, one 01' saidtiming devices having a relatively short predetermined time period toprovide said minimum time limit and the other said device having alonger predetermined time period to provide said maximum time limit,driving mechanism for said cyclic switch forming a part of saidoperating-mechanismand connected to be actuated by the firsttiming'device at the end of its timing period to return said switch tonormal to terminate ener' gization of said cross-road right-of-waycircuit, said first timing device being adapted to be reset to repeatits time period and having linkage with said traflic actuated meansrendered eflective by said cyclic switch in said cross-road period ofsuch switch to so reset said timing device by trafllc actuation wherebysaid crossroad period will be prolongedby such traiilc actuation withinsaid maximum time limit, and a latch device connected with said cyclicswitch to be rendered eii'ective by said switch for setting by anyactuation of said traflic actuated means at any time throughout saidhighway period. of said switch to maintain said operating mechanismoperative after such actuation to move said switch through its cycleinto its cross-road period, and to be released by said switch in saidcross-road period when said two timing devices are rendered eflective bysaid switch.

10. .A street crossing signalling system including a .pair 01' signalcircuits, one for the cross reet and one i'or the highway, switchingmeans having a normally inactive position and movable through a cyclefor alternately energizing said circuits, and returning to the normalinactive position, means for driving the switch, including a timecontrolled motor, which moves the switch through said cycle for timedperiods on the two streets, a vehicle operated detector in the crosslane momentarily operable to energize the motor, a first and a secondholding device adapted to hold the motor energized during the highwayand cross street right-of-way periods, means operated by the switch forreleasing the first holding device after the second holding device hasbecome effective to maintain the motor circuit energized, and means forreleasing the second holding device in the normal switch position unlessthe first device is operated by a vehicle actuation during the highwayposition, and two timing devices operable during the cross streetright-of-way period, each set into operation at the beginning of saidperiod and connected with the motor so that the first to releaseterminates the cross street period, the shorter timed device beingresettable by said vehicle actuated means when a vehicle actuationoccurs during its period.

11. An automatic signalling system for highway intersections includingsignal circuits arranged to provide a Go" signal for the main highwayand a "Stop signal for the cross street,

7 and circuits arranged to provide a Stop" signal for the main highwayand a (30" signal for the cross street, switching means to alternatelyenergize and de-energize the circuits through a cycle in which the G0"signal is taken from the main highway and given to the cross street fora predetermined period and then returned to the main highway for atleast a predetermined fixed minimum period, said switching meansnormally inactive for maintaining the 60" signal on the main highwaycontinuously, a switch adjacent to the highway to initiate the saidcycle of the switching means, and means associated with the switchingmeans to terminate the cycling of the switching means at the end of acycle.

12. An automatic signalling system for highway intersections includingsignal circuits arranged to provide a Go" signal for the main highwayand a Stop signal for the cross street, and circuits arranged to providea Stop" signal for the main highway and a "60 signal for the crossstreet, cyclic switching means to operate the signal through a cycle inwhich the (30" signal is taken from the main highway and given to thecross street for a predetermined period. and then returnedto the mainhighway for a predetermined fixed minimum period, said cyclic switchingmeans normally inactive maintaining the 60" signal on the main highwaycontinuously, means actuated by a vehicle to initiate the said cycle ofthe cyclic switching means, means associated with the vehicle-actuatedmeans to prematurely terminate, after a predetermined fixed minimumperiod of inaction of the vehicle means, that portion of the cycle inwhich the Go signal is given to the cross street, and means to retainthe effect of an impulse from a vehicle passing over thevehicle-actuated means during the period in which the cyclic switchingmeans is giving the Go" signal to the main highway until the Go signalis given to the cross street.

13'. An automatic signalling system for intersecting highways,comprising electric circuits for operating the signalling devices,switching devices cooperable for -normally causing a "Go" signal to beexhibited on one street and a Stop signal on the other, means associatedtherewith for moving said switching devices through a cycle of operationto cause said signalling devices to be actuated through said circuits soas alternately to indicate Stop and Go" signals respectively to theintersecting highways, means, including timing mechanism, for initiatingand terminating the operation of the switching devices, andvehicle-actuated means for energizing said time-controlled means 14. Atraffic signalling apparatus having, in combination, a traflic actuatedcontroller, right of way transferring mechanism controlled from saidcontroller, and signal timing mechanism having a predetermined maximumtiming period and a predetermined minimum timing period, said minimumperiod enlargeable up to the maximum period by action of saidcontroller.

15. A trafiic signaling apparatus for interfering trafdc lanes andhaving, in combination, a right of way indicating device, a trafficactuatable controller, right of way transferring mechanism controlledfrom said controller, and two devices controlled from said controllereach operable to control duration of right of way indication, one saiddevice cooperative to vary duration of right of way indication otherwiseresultant from the other, one said device having a predetermined maximumduration control period and the other said device having at least apredetermined minimum duration control period.

16. A traflic signaling apparatus for interfering traiiic lanes andhaving, in combination, a. right of way indicating device, a traflicactuatable controller, a combined right of way timer and right of wayshifter for said indicating device, a controller-actuated, right of waytimer, each said timer cooperable to time duration of right of wayduring a period of timing thereof by the other, said combined timer'andshifter having a predetermined maximum timing period and saidcontroller-actuated timer having a predetermined timing period less thansaid maximum.

17. A traflic signaling apparatus for interfering trafllc lanes andhaving, in combination, a right of way indicating device, a traiilcactuatable controller, a combined right of way timer and right of wayshifter for said indicating device, a

controller-actuated, right of way timer, one said timer cooperable totime duration of right of way during timing thereof by the other, saidcontroller-actuated timer cooperative to vary duration of right of wayindication otherwise resultant from the other timer, motor mechanism foractuating said combined timer and shifter, and a motor mechanism circuitmade and broken by actuation of said controller...

18. A traiilc signaling apparatus for interfering highway and crosslanes and having, in combination, a highway right of way controllingcircuit, a cross lane right of way controlling circuit, a switch,including contacts for making and breaking said controlling circuits,cooperable to 'shift right of way indication as between said lanes, 9.trafflc actuable controller in the cross lane, motor-mechanism having amake and break device in its circuit operable in response to actuation'of said controller to actuate said switch to make contact with saidcontrolling circuits one after the other so as to shift-right of wayindication back and forth between said lanes, and, in response toasingle actuation of said controller to compel remaking the highwaycircuit after the same is broken, and means whereby successive actuationof said controller during right of way in the cross lane and within apredetermined interval of time from each other, compels mutual contactof the switch contacts for the cross lane circuit to endure beyond atime caused by a single actuation of said controller during cross laneright of way.

19. A traific signaling apparatus for interfering highway and crosslanes and having, in combination, a highway right of way controllingcircuit, a cross lane right of way controlling circuit, a switch,including contacts for making and breaking said controlling circuits,cooperable to shift right of way indication as between said lanes, atrafiic actuatable controller in the cross lane, motor-mechanism havinga make and break device in its circuit operable in response to actuationof said controller to actuate said switch to make contact with saidcontrolling circuits one after the other so as to shift right of wayindication back and forth between said lanes, and, in response to asingle actuation of said controller to compel remaking the highwaycircuit after the same is broken, and means whereby successive actuationof said controller during right of way in the cross lane and within apredetermined interval of time from each other, compels mutual contactof the switch contacts for the cross lane circuit to endure beyond atime caused by a single actuation of said controller during cross laneright of way, duration of highway right of way being dependent on thetime period of contact between the switch, contacts for the highwaycircuit, and means, dependent for operation upon the passage of at leasta predetermined interval of time from a preceding actuation of saidcontroller, to arrest operation of said motormechanism.

20. A traffic signaling apparatus for interfering trafiie lanes andhaving, in combination, a right of way indicating device, a trafilcactuatable controller in one lane and means cooperable, by a singleactuation of said controllento cause transfer of right of way indicationto the lane of said controller from the other lane and compel durationof right of way indication in the lane of said controller for at least apredetermined period, and said means including a device cooperable tocause re-transfer to said other lane after a predetermined maximumperiod of duration in the lane of said controller.

21. An automatic signalling system for intersecting highways comprisingelectrically operated signalling devices, switching devices, meansassociated therewith devices through a cycle of operation to cause saidsignalling devices to alternately indicate "Stop" and "Go" signalsrespectively to the intersecting highways for predetermined periods, atimer for varying the cycle of operation of the switching devices andtrams-actuated means for initiating the operation of said switch-movingmeans and said cycle-varying means.

22. In an automatic signal mechanism for intersecting highways, thecombination with signal means at the intersection to normally provide a60" signal for the main highway while giving a "Stop" signal for theintersecting street and another normally inactive signal means toprovide a "Stop signal for the main highway while giving a 5G0" signalfor the intersecting street, of a signal current supply, signal circuitswitch devices and connections arranged to form a normal circuit throughwhich current is supplied to one for moving said switching.

of the signal means to produce a 60" signal for the main highway and aStop" signal for the intersecting highway, means including a timingmechanism, which when operated will move the signal circuit switchdevices in such an order as to change the signals from Go and Stopsignals for the main and cross highways respectively to Stop" and Go forsaid highways, and after a delay restore the circuits to their normalcondition, a switch adjacent to one of the highways, means operated bysaid highway switch for effecting an operation of said switch devices,and means associated with the switch devices to prevent a Go signal forthe cross highway beyond its normal time limit until after a Go" signalfor the main highway has been restored and maintained for a period oftime.

23. A trafiic signaling apparatus for interfering trafiic lanes andhaving, in combination, a right of way indicating device, a trafllcactuatable controller in one lane, and means cooperable, by a singleactuation of said controller, to cause transfer of right of wayindication to the lane of said controller from the other lane andretransfer to' the other lane and, after such retransier, compelduration of right of way indication in said other lane for at least apredetermined period before further transfer to the lane of saidcontroller.

24. A vehicle actuated trafilc signal comprising:' a pair of signalcircuits, a normally inactive switch having contacts for alternatelyenergizing said circuits, a motor for moving said switch from itsinactive position through a cycle alternately to energize said signalcircuits and return said switch to its inactive position, a. circuit forenergizing said motor, a vehicle operable detector for closing saidmotor energizing circuit, a time-controlled holding means actuated bythe detector and rendered operable by a control circuit through saidswitch in its normal position for holding closed said motor energizingcircuit, said control circuit being operated by said switch in travelingthrough its cycle for rendering said holding means operable through apart of such cycle and then releasing said holding means, after whichsaid holding means may again be operated by vehicle actuation, a secondtime-controlled holding means operated by said switch during its cyclewhich holds said motor energizing circuit closed at and after therelease of said first-mentioned holding means, said second meansreleasing at the end of its time period to deenergize said motor circuitand return the switch to its inactive position.

25. A street crossing signaling system including a'pair of signalcircuits, one for the cross street and one for the highway, switchingmeans having a normally inactive position and movable through a cyclefor alternately energizing said circuits, normally inactive timecontrolled means for moving said switching means through its cycle, saidmeans comprising motor means adapted to move the cyclic switch fromnormal position through cross street and highway positions and to thenormal position, an energizing circuit for said motor means, and a firstand a second holding device adapted to hold the motor circuit energizedduring the street timed periods, said motor means being adapted to movethe switch to the inactive position when the first holding device isreleased in the highway position and to move the switch past theinactive position into another cycle if said cross street for renderingsaid time controlled means active, comprising a trafllc actuated dc vicemomentarily operable to energize the motor circuit and operate theflrstholding device to maintain it energized, and means including theswitch for restoring the time controlled means to its inactive conditioncomprising means'operated by the switch for releasing the first holdingdevice after the second holding device has become eflective to maintainthe motor circuit energized, and means operated by the switch forrendering the second holding device operative over a time period in apart of the cycle at the end ofwhich

